1. Field of the Invention
The invention relates to an apparatus for punching CMP machine backing film; in particular, to an apparatus that can punch the backing-film of the CMP machine with enhanced efficiency and simplified procedure.
2. Description of the Related Art
In the past years, chemical mechanical polishing (CMP) has emerged as a critical technology in the area of wafer planarization for companies that manufacture integrated circuit (IC) devices. FIG. 1 shows a schematic view of a CMP machine, wherein the CMP machine shown consists of a shaft 1, a top ring 4 disposed on the shaft 1, a polishing slurry-distributing system 3, a platform 2, and a polishing pad 5 disposed on the platform 2. In addition, a wafer 6 is held by the top ring 4.
FIG. 2a and FIG. 2b are schematic views of the top ring 4, wherein FIG. 2a shows a surface of the top ring 4 connected with the shaft 1 of the top ring 4. The top ring 4 comprises a body 41, a guide ring 42, and a cover 43, wherein a closed space is formed between the cover 43 and the body 41. By connecting a port 431 of the cover 43 with a pumping system (not shown), the wafer can be vacuum-fixed by air holes 411, referring to FIG. 3f and FIG. 3g, located in the top ring 4. The body 41 and the cover 43 are coupled by plural screws 44, whereas the body 41 and the guide ring 42 are coupled by plural screws 45.
FIG. 2b shows the other surface of the top ring 4, on the opposite side, in contact with the polishing pad 5. In FIG. 2b, the guide ring 42 is disassembled. A backing-film 7, without being drilled, is adhered to this surface. As shown in FIG. 2c, a surface of the backing-film 7 is provided with a sticker 71 such that the unused sticker 71 is covered by a paper 72 to protect the adhesive surface of the sticker 71.
The conventional procedures for changing a backing-film described in detail hereinafter are in reference to FIG. 3a, FIG. 3b, FIG. 3c, FIG. 3d, FIG. 3e, FIG. 3f, FIG. 3g and FIG. 3h. Firstly, as shown in FIG. 3a, the top ring 4 is disassembled from the shaft 1. Then, after the guide ring 42 and the cover 43 have been disassembled from the body 41, the used backing-film is removed from the top ring 4. Referring to FIG. 3b, a new backing-film 7 as shown in FIG. 2c is positioned upon the surface of the top ring 4 that is to be in contact with the polishing pad 5. The backing-film 7 is aligned with the top ring 4 afterwards, and a portion of the paper 72 is then peeled off from the sticker 71, as shown in FIG. 3c. FIG. 3d shows the process of adhering the backing-film 7 onto the top ring 4, wherein the backing-film 7 is adhered to the top ring 4 and smoothed out completely by means of a roller 8, as shown in FIG. 3e. 
Referring to FIG. 3f, FIG. 3g and FIG. 3h, the process of drilling the backing-film 7 proceeds after the backing-film 7 is completely adhered to the top ring 4. Plural holes corresponding to the positions of the air holes 411 are manually drilled by means of a drill 9 with a 0.5 mm diameter. Then, the top ring 4 is turned upside down so as to re-drill the drilled holes from the other side by the drill 9 with a 0.7 mm diameter in order to smooth the drilled holes. The steps shown in FIG. 3f, FIG. 3g and FIG. 3h are repeated until all holes corresponding to the air holes 411 have been drilled. After the drilling process is completed, the guide ring 42 and the cover 43 are assembled to the body 41. The whole top ring 4 is then assembled to the shaft 1 to finish the backing-film replacement according to the conventional apparatus and method.
However, the conventional backing-film replacement has the following disadvantages:
1. The drilling process is typically difficult and laborious. Also, burr tends to be generated to cause an untrimmed edge of the drilled hole, which in turn may contribute to unstable and/or inefficient preventive maintenance (PM). As a result, the down time for the top-ring during a routine PM and QC (quality control) may prove to be long enough that productivity is affected.
2. The burr stated above can easily cause a bad finish on the wafer polishing or even the breakage of a wafer. Furthermore, the machine may be halted by such an error.
3. By means of the conventional backing-film replacement, it is difficult to locate the backing-film on the top ring.
4. Since the drills are expensive and easily damaged, the cost is increased.